Extending the base QuailTest class

To write a test for Quail, you need to extend the base class QuailTest. This class contains common helper functions for working with PHP's DOMDocument objects, plus a handy method to integrate with the reporting layers.

Once you have created your test and loaded it, you then need to add it to a guideline so that Quail will be able to include it. For running tests, however, you can use a method in Quail called getTest which runs a single test and returns the report array the test generated.
Required implementation

Once you have your class created, it must implement the method check(). That is the only required method which Quail will use to run a test. Test classes inherit the following variables:

• dom : Includes a full DOMDocument object of the page we are running tests against
• css : An instance of the QuailCSS object, which you can use to get CSS information about a element. Typically the only helper method used is getStyle($dom_element).
• path : An array of path information. If this is a test run against a local file or a URL, this will contain an array of the heirarchy to that path.
• base_path : The string representation of the above path variable.
• report : An empty report array which will contain the results of your test. You shouldn't need to touch this.
• default_severity : The severity level of the test

Adding to a report

Once you have run across an accessiblity error on a page, typically by walking the DOM or using Xpath queries, you can then add problems using the addReport() method. The first argument should be the DOMElement that contains the problem (optional) and then contains other parameters that are optional like a plain string message and a boolean operator representing if the test passed or failed (useful if the test applies to an entire page instead of a specific element).
Example

This is a test to find all images that lack an 'alt' attribute:

class imgHasAlt extends quailTest {
 
        var $default_severity = QUAIL_TEST_SEVERE;
 
        /**
        *       @var int The OAC test Number
        */
        var $oac_test = 1;
 
        /**
        *       @var int The test severity
        */      
        var $severity = QUAIL_TEST_SEVERE;
 
        /**
        *       The check method of this test. We are iterating through all img
        *       elements and tagging any without an ALT attribute.
        */
        function check() {
                foreach($this->getAllElements('img') as $img) {
                        if(!$img->hasAttribute('alt'))
                                $this->addReport($img);
                }
 
        }
}

Helper Methods

getAllElements

Returns an array of all elements. The first param can be a tag name, or you can instead opt to find all HTML elements that fall into a predefined group (param 2) as defined in the file common/elements.php